How much does the Milky Way weigh? Scientists have made precise measurements of our galaxy
Astronomers have reported making the most accurate measurements of the Milky Way’s mass to date. These calculations take into account stars and planets, dust and gas, and the supermassive black hole at the center of our galaxy. According to scientists’ calculations, the Milky Way has about 1.5 trillion solar masses.
The most accurate measurements of the Milky Way’s mass were based on data from the Hubble Space Telescope’a and the Gaia mission. Previous studies done over several decades have used rohe various observational techniques thatore have made it possible to estimate the mass of our galaxy in the range of 500 billionow to 3 trillionow solar masses.
– We wanted to know more precisely the mass of the Milky Way to put it in a cosmological context and porow to simulate galaxies in the evolving Universe,” said Roeland van der Marel of the Space Telescope Science Institute. – Lack of accurate knowledge of the mass of the Milky Way is a problem and does not allow to find answers to many questions in cosmology – added.
The results of the study have been accepted for publication on „The Astrophysical Journal”, and can now be consulted in the preprint archiveoIn arXiv.
The latest calculations show that the mass of the Milky Way is 1.5 trillion masses of our Sun. Of this mass, only a few percent is about 200 billionow stars in our galaxy. Another few percent is dust massow and gasow and a supermassive black hole located at the center of our galaxy, whichora alone has a mass of about 4 millionow masses of the Sun. The rest of the mass is the so-called. Dark matter – an invisible and mysterious substance thatora acts as a scaffold throughout the Universe and holds stars in their galaxies.
Although we cannot see it, dark matter is the dominant form of matter in the Universe. If we cannot observe it directly, how to estimate its mass? Scientists have used the speed of globular clusters to do just that – groupings of stars bound together by gravity and orbiting wokoł disk of the galaxy.
The more massive the galaxy, the faster the globular clusters move under the influence of its gravity. Most previous measurementsow took into account the speed at which globular clusters approached or moved away from Earth. However, thanks to the Hubble telescope’a and the Gaia mission scientists are able to record the lateral motion of globular clusters, with which theorych we can calculate the total velocity and therefore the mass of the galaxy.
New estimates of the mass of the Milky Way allow cfoto compare it with other galaxies. The lightest galaxies have about a billion solar masses. The most severe 30 trillionoin the masses of the Sun.
Hubble's and Gaia’s observations are complementary. Gaia was designed with the sole purpose of creating accurate, trojdimensional map objectoin astronomical across the Milky Way and track their movementow. Accurate measurements of the object have been madeow, including globular clusters. Hubble has a smaller field of view, but can measure fainter stars and thus reach further clusters.
The second published data set from the Gaia probe includes measurements of 34 globular clusters 65,000 light years away from Earth. Added to this are data from a decade of Hubble telescope observations'a, whichore include measurements of 12 globular clusters 130,000 light years away from Earth. When measurements from the Gaia mission and the Hubble telescope’and were connected as control points, much like pins on a map, astronomers were able to estimate the mass of the Milky Way more accurately than ever before.